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Title: The thermodynamics of proton hydration and the electrochemical surface potential of water

Abstract

The free energy change for transferring a single ion across the water liquid/vapor interface includes an electrochemical surface potential contribution. Since this potential is not directly accessible to thermodynamic measurement, several extra-thermodynamic approaches have been employed to infer its sign and magnitude, with a resulting wide spread of values. Here, we examine further the thermodynamics of proton hydration and the electrochemical surface potential of water along three directions: (1) a basic relation of interfacial electrostatics and experimental results on ion distributions near a water/organic interface are employed to infer a solvent contribution to the electrochemical surface potential, (2) a re-analysis is performed of the existing bulk and cluster ion hydration data, and (3) extensive computational modeling is conducted to examine the size dependence of hydration enthalpy differences for the NaF ion pair between the small cluster and the converged bulk limits. The computational studies include classical polarizable models and high-level quantum chemical methods. The new theoretical analysis of existing experimental data and the combined classical/quantum modeling lead to results consistent with our previously derived proton hydration quantities.

Authors:
 [1];  [1]
  1. Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221 (United States)
Publication Date:
OSTI Identifier:
22311338
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 141; Journal Issue: 18; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ENTHALPY; FREE ENERGY; HYDRATION; INTERFACES; ION PAIRS; IONS; LIQUIDS; PROTONS; SIMULATION; SODIUM FLUORIDES; SOLVENTS; SURFACE POTENTIAL; VAPORS; WATER

Citation Formats

Pollard, Travis P., Beck, Thomas L., and Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221. The thermodynamics of proton hydration and the electrochemical surface potential of water. United States: N. p., 2014. Web. doi:10.1063/1.4896217.
Pollard, Travis P., Beck, Thomas L., & Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221. The thermodynamics of proton hydration and the electrochemical surface potential of water. United States. https://doi.org/10.1063/1.4896217
Pollard, Travis P., Beck, Thomas L., and Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221. 2014. "The thermodynamics of proton hydration and the electrochemical surface potential of water". United States. https://doi.org/10.1063/1.4896217.
@article{osti_22311338,
title = {The thermodynamics of proton hydration and the electrochemical surface potential of water},
author = {Pollard, Travis P. and Beck, Thomas L. and Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221},
abstractNote = {The free energy change for transferring a single ion across the water liquid/vapor interface includes an electrochemical surface potential contribution. Since this potential is not directly accessible to thermodynamic measurement, several extra-thermodynamic approaches have been employed to infer its sign and magnitude, with a resulting wide spread of values. Here, we examine further the thermodynamics of proton hydration and the electrochemical surface potential of water along three directions: (1) a basic relation of interfacial electrostatics and experimental results on ion distributions near a water/organic interface are employed to infer a solvent contribution to the electrochemical surface potential, (2) a re-analysis is performed of the existing bulk and cluster ion hydration data, and (3) extensive computational modeling is conducted to examine the size dependence of hydration enthalpy differences for the NaF ion pair between the small cluster and the converged bulk limits. The computational studies include classical polarizable models and high-level quantum chemical methods. The new theoretical analysis of existing experimental data and the combined classical/quantum modeling lead to results consistent with our previously derived proton hydration quantities.},
doi = {10.1063/1.4896217},
url = {https://www.osti.gov/biblio/22311338}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 18,
volume = 141,
place = {United States},
year = {Fri Nov 14 00:00:00 EST 2014},
month = {Fri Nov 14 00:00:00 EST 2014}
}